Spring Startup Woes

[digger]

As per Sidecar Bob above, good ideas to check 1. 2. and 3. I would add 4. Similar to 3. The two halves of the plenum have a seal between them, mine was bad a few years ago and gave me the same situation you are in. With a full tank I could turn on the petcock (engine not running) with the air cleaner removed and see fuel puddling in the bottom of the plenum. Mine ran great when put away for the winter, and acted up during first start-up in the Spring.

[Dirty Dave]

Will do.

Thanks again.

Replaced the plenum seal last rebuild. Took everything apart.

Ran the bike without the air box this time and saw the plenum was wet with gas.

Normal/not normal?

[gltriker]

(***POST#18

SNIP
Replaced the plenum seal last rebuild. Took everything apart.

Ran the bike without the air box this time and saw the plenum was wet with gas

DSCN1243 D ring deterioration.JPG

DSCN1223 plenum seal.JPG

Float set - brass seat and filter screen.jpg

[Dirty Dave]

As per Sidecar Bob above, good ideas to check 1. 2. and 3. I would add 4. Similar to 3. The two halves of the plenum have a seal between them, mine was bad a few years ago and gave me the same situation you are in. With a full tank I could turn on the petcock (engine not running) with the air cleaner removed and see fuel puddling in the bottom of the plenum. Mine ran great when put away for the winter, and acted up during first start-up in the Spring.

Sorry Digger. Missed the last part.

[Dirty Dave]

SNIP
Replaced the plenum seal last rebuild. Took everything apart.

Ran the bike without the air box this time and saw the plenum was wet with gas.

Normal/not normal? DAVE!

DSCN1243 D ring deterioration.JPG
DSCN1223 plenum seal.JPG

Oh crap !

Thanks?
(work to do)

[Dirty Dave]

Okay... bear with me.

New oil and plugs as there was a lot of smoke and dripping fluids from left exhaust.

Started up and ran nicely on all fours until it saw me smile and THEN started acting up.
Sounds like it's running on 2 then four... smoking outta left exhaust and dripping out (oil/gas) of same.

I'm thinking head gasket even though compression yesterday was good.
Replaced the right side and freshened it up last year. No problem there.

Opinions?

[Sidecar Bob]

Deal with the fuel in the plenum first. It could be flooding one or more cylinder and causing it/them to cut out until it blows the fuel out to the exhaust.

There's probably no oil in the gas coming out of the exhaust. More likely it is just washing some of the accumulated soot out.

[Dirty Dave]

I hate it when you're right.

At least I was clever enough not to completely assemble everything.

[5speed]

if there is oil coming out the exhaust it could be due to the gas washing the cylinder walls down although I don't think there would be enough to notice it..

[redglbx]

Dave, the really biggest problem with all Keihin carbs imho, is that they easily varnish up the low speed/idle circuits, because they are really, really small at .0135in. If you pull the carbs again (they really should be installed with zippers & Velcro) I would take a can of gumout carb cleaner and sand the plastic straw down to a point, access the idle jets and make sure you can blow carb cleaner through that circuit, it should come out of the very small hole in the carb bore that the mixture screw slightly protrudes through. If it doesn’t easily blow through then you start looking for what’s plugged which will probably be the idle jet itself.

Keep in mind the hole size on that jet is .0135in, I do not recommend drilling it in any way shape or form, there are several tools out there for doing this like a welders torch head jet cleaner that goes goes down usually to sizes smaller than the .0135in opening in the jet. That circuit must be able to flow carb cleaner freely for it to work correctly in your bike. And when you think you have it clean do it again because it’s probably not. And unless you’ve got the zipper/Velcro installation upgrade in your rack you will be cussing ! So just clean it again.

Might as well clean your slides & caps while you’re there as well.

One other thing I’ll add on the plenum, last year Idid a set of LTD carbs for a friend (they were a complete mess) and initially I went through the bike and got it running quite well after the carb rebuild, new Dyna coils & ignition, and the bike ran very well. So my friend came and picked it up (lives in Ohio) but called the next day to tell me it was running terribly and flooding so I asked he to pull the air cleaner which he did and found the plenum flooded (shite !) , so he mailed just the carbs back and I set it up on my bench with my fuel bottle and sure enough the plenum was leaking. (Shite)

I rebuilt these carbs using the Randakks premium kit so I contacted them because the seal between the halves had to be leaking right ? Randakks generously sent me a new seal which I installed and figured I was now good to go,,,,, nope ! All kinds of gas in the plenum again. I now went through every seal and surface very carefully looking for defects and making sure all sealing surfaces were clean and flat.

The odd thing I noted was that when I turned the fuel bottle on fairly quickly I had fuel running from the plenum area in the corner by the #1 carb, didn’t make sense, so a little more time investigating found that this plenum had porosity in that corner that would leak when the fuel was turned on. A replacement plenum sourced from the owner was actually more porous than the first. A third plenum sourced from my friend “fast Eddie” here was perfect and the problem was fixed. Set your carbs up on the bench and check them for flooding with a fuel bottle BEFORE putting them back into your bike.

As a side note the oe owner of this Ltd always complained about how badly the carbs worked on it and he rode the crap out of it. Ultimately he switched to 1100 carbs as a hoped for fix but still complained about it carbureting poorly. It came to me with the 1100 carbs installed. Whatifound was a mix/match of carb bodies & parts. So the current owner went back & found what we thought were the oe Ltd carbs, what I found was 2 oe LTD carbs, a 75 carb and a 79 “California” spec’d carb, no wonder it ran like poo ! The 75 carb is jettedthe richest of all 1000 carbs and the 79 California (didn’t know these existed) were jetted extremely lean. Just ran like crap!

So a lot of time was spent sourcing the correct “matched” carbs and it ran sweetly until the whole plenum porosity leaking thing started. So do not mix & match carbs, you must use 4 of the same year and model number. This is a must do thing imho !

[Rednaxs60]

Might think about a small ultrasonic cleaner, one that will accommodate a single carb.

[redglbx]

A ultrasonic cleaner is a very good investment imho.

[Sidecar Bob]

A varnished jet won't cause fuel to pool in the plenum.

[Dirty Dave]

Thanks all for your generous responses.

The zippers & Velcro idea is great. Working on that.

I have an ultrasonic cleaner and Chem-Dip(ed) the whole shebang last year.
Was rewarded with a great running Wing until stored.

My Mityvac "bit the big one" so I tried a rebuild but failed at that too. New one
is on the way to pressure test carbs after another tear down.

Really am curious to see, if possible, what went wrong. I like wrenching so
will keep the Wing as an educational tool rather than a viable source of transportation.



My 78 never gave me problems, neither my 84 Aspencade. Hmmm.

[redglbx]

Bob, absolutely correct ! No pooling but it will make things run poorly at idle and low speed and hard starting which is where I was going with that.